The cuddly alfalfa weevil

Note the proboscis and dark median stripes characteristic
of the alfalfa weevil.

Each year in pest control brings a few surprises.  This year's early surprise is a small outdoor insect known as the alfalfa weevil, Hypera postica. The alfalfa weevil is a small, 3/16-inch (5 mm) long, brownish-grey weevil with a darker brown band down the back. It normally spends the winter as an adult at the base of clover or alfalfa plants, or under leaves or other debris outdoors.

Now weevils are pretty interesting insects, with some of the, if not beautiful, most bizarre-looking faces and life styles among the beetles. Only a few weevils ever become pests--at least indoors. The rice and granary weevils are probably two of the most common, and can be found associated with stored rice and whole grains.

In the twenty years that I've been answering phone calls from county extension agents and citizens I don't recall receiving any complaints about alfalfa weevils invading homes or structures.  This year must be different.  Over the past few weeks I've had several calls and emails about alfalfa weevils (1) being found indoors, (2) being found in large numbers on the outside of homes, and (3) being found in beds (three complaints!). 

OK. There is no good reason why alfalfa weevils should be interested in a bed--unless they just like to cuddle.  Alfalfa weevils do not bite and certainly are not blood suckers.  I can only guess that these insects must be good at climbing up folds of fabric hanging down from a bed. Also, bedrooms and beds tend to be located at the exterior perimeter walls of home.  And certainly one of the easiest places to spot these small gray weevils would be on white bed linens.

Although I can't confirm that alfalfa weevils fly, it's possible that these insects are being drawn to external lighting, and subsequently indoors.  If you are servicing a home that is under siege from alfalfa weevils, standard recommendations for control of occasional invaders should apply: (1) reduce or eliminate outdoor lighting, especially lights that shine or doorways or shine directly on the sides of the home; (2) seal doors, windows, and cracks or gaps in walls, soffits or foundations; and (3) apply a residual insecticide to foundation perimeters and around potential entry points into the structure.  Indoor pesticide applications, including aerosol bombs, are not recommended.

The great beetle invasion

It's fall, and for most Texans this means principally and foremost, the beginning of football season.  But while high school males are rejoicing at the end of two-a-days and the beginning of cheerleaders, another species is rejoicing in the change of weather.

The sugarcane beetle, Euetheola humilis, is found throughout the South.  First reported as a pest of sugarcane in Louisiana in 1880, it is considered an occasional pest of field corn, rice and sweet potato. In recent years it appears to be becoming an increasingly important pest in Louisiana and Mississippi.  In Texas I have received increasing reports of this beetle from unusual urban situations.  Schools have reported damage occurring to running tracks.  Businesses have reported damage to caulking in sidewalks and around doors of buildings and, last year, a car dealership reported beetles digging their way into rubber seals on recreational vehicles in a sales lot.

Black piles of sugarcane beetles at high school running track, Paris, TX.  September 13, 2010. 
Photo by Sam Adams, Pogue Construction

This week I received pictures showing the most impressive infestation I have seen or heard of so far.  The new high school running track in Paris, Texas has been inundated with these beetles attracted, apparently to stadium lights.  

Such infestations seem to be sporadic, as these beetles are not abundant in all years; but when they are, they are showing themselves to be a formidable pest.  Like crickets and many other occasional pests, sugarcane beetles are attracted to lights at night.  When sun comes up, the beetles' natural instinct is to get out of the light.  What makes this species different is its persistence, ability and strength to dig through rubbers and caulks and other usually tough building materials.  

Sugarcane beetles lift a rubberized running track off its cement base
via their digging activities. 

As with fall cricket invasions, the best and fastest solution is to turn off the lights.  In the Paris, TX high school last night, lights were turned off with a dramatic decrease in numbers.  But turning off lights is not always practical or possible.  In such cases, reducing the time that lights are left on, switching to less attractive sodium vapor light fixtures, or some combination of the two strategies should be pursued.  Pesticides are not likely to provide much relief, though frequent treatment with a residual insecticide may be somewhat useful in emergency situations like the high school where the track is being destroyed.  Early morning sweeping or vacuuming, before the beetles can cause damage, may also be helpful in some cases.  

The only good news about this situation is that such flights are temporary and will probably decline within a week or two.  Football and track coaches, however, may still not be pleased.

Seed bugs common in many areas

One of the occasional invaders of structures that we see in Texas is actually a family of insects called the seed bugs (Order Hemiptera: Family Lygaeidae).  There are some beautiful little insects in this group (see the picture to the right, taken by entomologist Mike Quinn on Bugguide.net, of a species called Pseudopamera aurivilliana), most of which are overlooked by the casual insect observer because they stay in the fields and roadsides and feed only on, well, seeds.

Seed feeders don't hurt the plants they feed on, but they do reduce seed production.  Lygaeid bugs are just another part of the natural balance helping keep plant populations from getting out of hand.  

Some years we see high populations of a variety of these seed bugs, and this seems to be one of these years.  Entomologists from El Paso, Uvalde and other parts of south Texas are reporting invasions of false chinch bug, another type of Lygaeid this summer.

I recently had pictures of what appear to be Pseudopamera submitted by James Kiening (Bugmobile) through Martyn Hafley (Estes, Inc.).  The insects were clustered on what appeared to be building siding.  Also, John Stewart (Commercial Pest Control, Dallas) sent in samples of Ozophora picturata (see picture to right) that was clustering by the thousands outside a home in Dallas a couple of weeks ago (30 June). 

While interesting and useful to document the species that enter buildings, the bottom line for a customer with a Lygaeid infestation is that these are outdoor-living insects.  They show up only accidentally inside buildings (once they get indoors they have nowhere to go and nothing to eat).  If they enter a home or business it will be a temporary nuisance.  They will not reproduce or set up shop indoors.  If significant numbers show up indoors it's probably an indication of the need to seal windows, doors, air vents, etc.  Also take a look at outdoor lighting to see if unnecessary lights are being left on all night, especially lights shining on doors, windows or sides of the structure. 

P.S., I'm told by Ed Riley of the entomology museum at Texas A&M University that the Hemipteran family Lygaeidae is being split into multiple families by the meddling DNA-obsessed taxonomists.  I was encouraged to know that even he didn't recall the new families for these little guys, so we just agreed to keep calling them all Lygaeids until we're arrested by the entomology police.

Know your beetles

In baseball the difference in batting average between a mediocre hitter and an MVP is often just a few percentage points. In pest control the difference between someone who comes across as a skilled professional and someone who is seen as little more than a hired "bug sprayer" is in the details--like being knowledgeable about the unusual pests. If you want to build customer respect and loyalty there is nothing better than knowing your "bugs".

New technicians typically get trained to identify the most "important" or common pests: cockroaches, rats and mice, structural ant pests, fire ants, and termites. But as time goes on, alert technicians should be adding to their repertoire of pests that they can diagnose. Many of these will be occasional invaders, arthropods that usually live outdoors but can invade buildings when the weather conditions are right or when populations are unusually heavy.

This week's odd, occasional pest is the carabid, or ground beetle. Rather than a specific type of insect, this is a general name for a whole family of beetles. Carabids are most often considered beneficial predators, patrolling the ground for caterpillars and other larvae, even occasionally snails. Carabid beetles are quite common and diverse with over 2200 types in North America. Carabids vary in appearance, but are long-legged and have thread-like antennae which arise between the antennae and mandibles. The body is usually shiny, has lengthwise grooves (striae) on the wing covers, and most often the color is black.

Some species of ground beetles emit noxious secretions as a type of self defense. This morning I picked a ground beetle off the floor of my home. After disposing of it, my fingers carried a strong vinegar-like smell. While not irritating in my case, some species produce compounds that can be irritating to human skin.

Occasionally carabids cause more serious problems. Two weeks ago I received a sample of ground beetles (above) burrowing through sealant around the doorway of an office. Behavior like this can be puzzling unless we understand more about the biology of carabid beetles. In this case the behavior is not surprising considering the daily (circadian) behavior of the beetles.

Carabid beetles are nocturnal, being active mostly at night. They are rapid runners and rarely fly except during mating season (we'll return to this point). Like all nocturnal insects, carabids are negatively phototaxic during the day, that is their instinct is to move away from light. So while we're rubbing the sleep out of our eyes and picking up our morning paper, carabids are looking for dark crevices or digging down into the ground to escape daylight. And carabids, with their flimsy looking legs are very good diggers. If you don't believe me, try holding one in your closed hand for a few moments. Their power to squeeze between fingers is amazing.

This morning I received a call about an RV dealership who was having a problem with some sort of "beetle" digging into rubber sealant used around skylights on their campers, "just like a mouse gnawing into a box". These turned out to be scarab beetles, a slightly different critter, but one with the same behavior as carabids. Over the years I've received similar calls from high school track coaches dismayed by beetles boring into rubberized tracks, churches experiencing leaks when ground beetles started boring through the waterproof foam material on the roof, and schools and businesses concerned about all the "bugs" on the floor. In all cases these beetles were caught in an artificial setting at the end of the night, and simply did what comes naturally: they located a soft crevice into which they diligently burrowed to escape the light.

So what can be done? First, it's important to remember that ground beetles normally would have no interest in visiting a car dealership, athletic field or home. But they will show up at these places if attracted by nighttime lighting. Although carabids do not normally fly, and are negatively phototaxic during daylight hours, things change during mating season. For a few days out of the year, each species of carabid beetle becomes an active flier at night. Also, like other nocturnal flying insects (e.g., crickets), lights such as outdoor floodlights, athletic field lights, security lights, even lit windows become very attractive during these flights.

Like crickets, the first step in solving a heavy carabid beetle problem is to reduce or eliminate outdoor lights during these nocturnal flight periods. The good news is that each species of carabid typically has a short flight period--a few days to a week or so. Even reducing or eliminating lights for a week may be long enough to get beyond the flight period for a given beetle. Pesticides are not likely to be an effective solution to these insects because the beetles are exposed for a relatively short time to spray residues and the damage is done quickly.

A more permanent solution for carabid beetles and other nocturnal flying insects is to look at positioning or type of lighting. Lights should not be shined directly on doorways or windows (or in the case of our RV dealer, above valuable vehicles with rubber seals). Some lights are less attractive to insects than others; for example, sodium vapor lights tend to be less attractive to night-flying insects than mercury vapor or halogen bulbs. Also, using lights with proper shielding to prevent light pollution has a side benefit of being less likely to attract insects from long distances.

Even knowing what's bugging your customer may not bring them full satisfaction. In the case of ground beetle "invasions" there's no quick fix apart from turning out the lights. But a quick identification and explanation (or prompt delivery on a promise to find out), you will certainly gain the appreciation and greater respect of your customers.